Reduction Of Potassium Permanganate Research Articles

Operando Spectroelectrochemical Imaging of Concentration Fields and Tafel Kinetics in Microfluidic Electrochemical Devices.

With the development of microtechnologies for energy conversion and storage, mass transfer and micromolar concentration variations need to be measured at the microscale. These advances need to be accompanied by novel imaging techniques with the capability of achieving high spatial resolution while detecting very small signal variations (less than 0.1%). Thus, in this study, a new microscopy technique is proposed based on a combination of electrochemical impedance spectroscopy (EIS) and visible imaging spectroscopy to measure the concentration fields at the micromolar scale in operando microfluidic fuel cells (MFCs). This technique exploits EIS modulation and Fourier analysis to reduce the noise during concentration field imaging. A mass transfer model in the periodic regime is derived to validate the measurements and to estimate the Tafel kinetics and mass diffusivities during potassium permanganate reduction from only one potential measurement. The proposed imaging method and mathematical framework presented in this study can be used to study binary electrochemical reactions without gas production.

Potential in-vitro antioxidant and anti-inflammatory activity of Martynia annua extract mediated Phytosynthesis of MnO2 nanoparticles

The present research work describes the phyto-synthesis of Manganese dioxide nanoparticles (MnO2NPs) from the reduction of potassium permanganate using Martynia annua (M.annua) plant extract. From the literature review, we clearly understood the M.annua plant has anti-inflammatory activity. Manganese dioxides are important materials due to their wide range of applications. Their increased surface area gives them distinct capabilities, as it increases their mechanical, magnetic, optical, and catalytic qualities, allowing them to be used in more pharmaceutical applications. A detailed review of literature highlighting the issues related to this present work and its knowledge gap that none of the inflammatory activities had been done by MnO2 NPs synthesized from M.annua plant extract. So we selected this study. The product MnO2 NPs showed the wavelength centre at 370 nm and was monitored by UV–Vis spectra. The wave number around 600 cm−1 has to the occurrence of O–Mn–O bonds of pure MnO2 confirmed by FTIR spectroscopy. Transmission electron microscopy images showed the morphology of MnO2 NPs as spherical-shaped particles with average sizes at 7.5 nm. The selected area electron diffraction analysis exhibits the crystalline nature of MnO2 NPs. The obtained MnO2 NPs showed potential antioxidant and anti-inflammatory activity was compared to the plant extract. The synthesized MnO2 NPs have a large number of potential applications in the field of pharmaceutical industries. In the future, we isolate the phytocompounds present in the M.annua plant extract and conduct a study against corona virus. MnO2 produces manganese (III) oxide and oxygen, which increases fire hazard. But further research is required to understand their environmental behaviour and safety.

Green synthesis of Plectranthus amboinicus leaf extract incorporated fine-tuned manganese dioxide nanoparticles: Antimicrobial and antioxidant activity

Plectranthus amboinicus Manganese dioxide (PA-MnO2) nanoparticles were synthesized by the reduction of potassium permanganate (KMnO4) using Plectranthus amboinicus (P. amboinicus) leaf extract at room temperature. A dark brown colour appeared after the addition of leaf extract to the solution of KMnO4. PA-MnO2 nanoparticles showed absorbance maximum at 324 nm. Scanning Electron Microscopy (SEM) study of particle size and morphology revealed that PA-MnO2 nanoparticles have spherical structures in shape. The electron dispersive X-ray spectroscopy confirmed the presence of Mn and O in the sample. Fourier Transforms infrared spectra of PA-MnO2 nanoparticles show the occurrence of O-Mn-O vibrational mode at around 515 cm-1. Based on the spectral and morphological data confirms the prepared compounds are nanometer in size. The structural investigation of MnO2 nanoparticles using the powder X-ray diffraction method reveals that the nanoparticles have a tetragonal configuration. Powder X-ray diffraction measurements were used to estimate crystallite grain diameter. The size of the crystalline grains is 7.5 nm. The PA-MnO2 nanoparticles demonstrated enhanced antibacterial activity against various gram positive bacteria like as S. aureus, S. pneumoniae, Stap. Pneumoniae and B. subtilis and various gram negative bacterial strains like as E. coli, K. pneumoniae, p. mirabilis and P. aeruginosa than standard drug ciprofloxacin. Antifungal activity of PA-MnO2 nanoparticles exhibited abnormal character against various fungal strains such as A. niger, C. albicans, C. tropicalis and M. campestris than the standard drug nystatin. Free radical scavenging study by DPPH assay showed enhanced activity by increasing the concentration of PA-MnO2. This study shows simple and eco-friendly synthesis of PA-MnO2 nanoparticles by plant extract. PA-MnO2 nanoparticles by green approach have potential to resolve emerging drug resistance against pathogenic diseases.

Spectrophotometric assay of oxymetazoline-HCl in pure form and in its pharmaceutical formulations using potassium permanganate.pdf

This study involves the development of two sensitive and reproducible spectrophotometric methods to determine oxymetazoline- HCl in pure form and its dosage forms. Both spectro-photometric methods were based on the reduction of potassium permanganate with oxymet-azoline- HCl.In method (A), oxymetazoline-HCl was reacted with an excess known amount of potassium permanganate in an acid solution of H2SO4 and the absorbance of unreacted potassium per-manganate was measured at 545 nm. In method (B) the oxidation reaction of oxymetazoline- HCl was carried out in an alkaline solution of sodium hydroxide and the absorbance of the resulting (MnO2) was measured at 610 nm. In method (A), the amount of potassium perman-ganate reacted corresponds to the oxymetazoline-HCl content and the intensity of absorb-ance decreased linearly with the concentration, while in method (B), the intensity of absorb-ance was increased linearly with concentration.Under optimum conditions, Beer’s law was found to be linear in the concentration range of 1.0-30 and 0.5-3.5 μg/ml with molar absorptivity 0.64×104 and 3.16×104 l.mol-1cm-1and cor-responding to Sandell's sensitivity values of 0.0448 and 0.0090 μg/cm2 for both methods (A) and (B), respectively. The detection limit (LOD) and quantification limit (LOQ) have also been estimated. Accuracy for pure OXM was calculated and found in the range -0.7% to 0.8% and-2.68% to 0.614%, while the precision (RSD) was <0.176% and <0.929% for method (A) and method (B), respectively. The two suggested methods (A) and (B) were successfully applied to the determination of oxymetazoline -HCl in bulk and its pharmaceutical preparations (drops and spray) with accurate and accepted results.

Preparation and Optimization of MnO2 Nanoparticles

Manganese dioxide (MnO2) is one of the commonly applied inorganic material which is gaining increasing attentions in recent years. However, preparation and optimization of MnO2 nanoparticles have rarely been studied by previous studies, making the mechanisms responsible for preparation of MnO2 remaining largely unknown. Here in this study, we synthesized MnO2 through reduction of potassium permanganate (KMnO4) using different reductants, including protein, polymers and small molecule organic acids. It was suggested that, stable MnO2 nanoparticles can only be obtained in balanced synthesis/stabilization process which requires the reductant to have proper reducibility and stabilization ability at the right charge ratios. Our results concluded that, among these materials, polyvinylpyrrolidone (PVP) K30 showed the best performance at the charge ratio of 8/3 (w/w, PVP K30 to KMnO4, under given reaction conditions, which resulted in nanoparticles (hydrodynamic size: 79.72±31.53) with high stability and well dispersity, which was then selected as the optimal formulation.

Biogenesis of MnO2 Nanoparticles Using Momordica Charantia Leaf Extract

In this present study, an easy, eco-friendly, and efficient method for the biogenesis of manganese dioxide nanoparticles (MnO2 NPs) using Momordica charantia leaf extract is discussed. The MnO2 NPs were synthesised by reduction of potassium permanganate using Momordica charantia leaf extract as a reducing agent. Fourier-transform infrared spectra exposed the contribution of the biomolecules in the Momordica charantia leaf extract for the formation of MnO2 NPs. The UV–visible spectrum of the biosynthesized MnO2 NPs displayed absorption peaks at 371 nm, which was the absorption maximum of MnO2 NPs. Crystal phase and crystalline size of the biosynthesized MnO2 NPs was characterized by X-ray diffraction analysis. The X-ray diffraction pattern indicated that the average size of MnO2 NPs was about 36.01 nm. The field emission scanning electron microscopy analysis revealed that the biosynthesized MnO2 NPs have irregularly spherical shape with 16 – 63 nm in size. EDAX confirmed the presence of Mn and O in the MnO2 NPs. The antibacterial activities of MnO2 NPs were evaluated against Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus cereus. The total antioxidant capacity was evaluated by phosphomolybdenum method. The biosynthesized MnO2 NPs have significant antibacterial activity and antioxidant activity.

Green Synthesis of MnO2 NPs Using Blumea lacera Leaf Extract and its Antimicrobial Study

Background: Green synthesis of nanoparticles has emerged as an interesting and expanding research area due to environmental friendliness, non-toxicity, cleanliness, and cost-effectiveness. Moreover, it can be performed at room pressure and temperature. Blumea lacera is described as a valuable medicinal plant in many vital systems of medicines. The study explored the eco-friendly green synthesis of MnO2 NPs using Blumea lacera leaf extract. Methods: Reduction of potassium permanganate (KMnO4) using Blumea lacera leaf extract was carried out at room temperature. The crude extract of Blumea lacera was added to metal ion reagents of specific volume and specific concentration at ambient temperature and stirred continuously using a magnetic stirrer. The aqueous leaf extract reduced and stabilized the KMnO4 into MnO2 NPs. The MnO2 NPs obtained from the solution were purified and separated by repeated centrifugation using Remi cooling centrifuge model C-24. Results: The biosynthesized MnO2 NPs characterized by UV–Vis spectroscopy showed an absorption peak at 400 nm. The XRD studies revealed the spherical shape of MnO2 NPs with an average particle diameter of 20 nm. FT-IR analysis confirmed the presence of functional groups -OH, C=O, C=C, and CH triggering the synthesis of MnO2 NPs. Vibrational mode at around 606.62 and 438.81 cm−1 supports the occurrence of the O–Mn–O bond. Conclusion: The synthesized MnO2 NPs were found to be good antibacterial and antifungal agents against bacterial strains Staphylococcus aureus, B. subtilis, Pseudomonas aeruginosa, E. coli, and fungal strains C. albicans, Aspergillus niger, and Sclerotium rolfsii.

Nitrocellulose redox permanganometry: A simple method for reductive capacity assessment

We propose a rapid, simple, and robust method for measurement of the reductive capacity of liquid and solid biological samples based on potassium permanganate reduction followed by trapping of manganese dioxide precipitate on a nitrocellulose membrane. Moreover, we discuss how nitrocellulose redox permanganometry (NRP) can be used for high-throughput analysis of biological samples and present HistoNRP, its modification used for detailed analysis of reductive capacity spatial distribution in tissue with preserved anatomical relations.•NRP is a rapid, cost-effective, and simple method for reductive capacity assessment•NRP is compatible with a high-throughput screening of solid and liquid biological samples•HistoNRP exploits passive diffusion slice print blotting for reductive capacity spatial analysis

MnO2/CoO electrode for supercapacitor: Synthesis and electrochemical performance

In this work, Cobalt Oxide (CoO) was prepared by co-precipitation method by taking 1:3M of Co (NO3)2·6H2O and NaOH. Synthesis of Manganese dioxide (MnO2) was done by reduction of potassium permanganate (KMnO4) with aqueous sulphuric acid (H2SO4) by hydrothermal process. For making the coin cell capacitor CoO and MnO2 were spin-coated on the thin copper sheet which was used as the current collector, PEDOT: PSS poly (3,4 – ethylene dioxythiophene) as electrolyte and cellulose paper as a separator. Scanning electron microscopy (SEM) analysis has been employed to study surface morphology and to confirm the formation of nanoparticles. An image analysis approach using ImageJ has been used to measure the percentage of porosity from the SEM micrographs. The parameters like specific capacitance, energy density, and power density were calculated from the CV measurements and were compared. When both electrodes are MnO2, it has a specific capacitance of 33.57F/g, the energy density of 16.84 J/g, and power density of 4.21 W/g and when both electrodes are CoO it has a specific capacitance of 29.19F/g, the energy density of 14.59 J/g and power density of 3.65 W/g. But one side with MnO2 and the other side with CoO electrode shows a specific capacitance of 44.92F/g, an energy density of 22.46 J/g, and a power density of 5.62 W/g.

Spectrophotometric determination of Metronidazole antibacterial drug via oxidation with alkaline potassium permanganate

Highly simple, sensitive and selective method is developed for the spectrophotometric determination of Metronidazole (MDZ) antibacterial drug either in pure form or in pharmaceutical formulations. This method is based on reduction of potassium permanganate by Metronidazole drug in sodium hydroxide solution to give green manganate ion which recorded at 610 nm. The method produced linear responses in the concentration range 4.28 – 59.91 µg mL−1 with limit of detection (LOD) and limit of quantification (LOQ) 0.21 and 0.69 µg mL−1 for Metronidazole drug respectively. The apparent molar absorptivity is 0.865 × 104 L mol−1 cm−1, Sandell sensitivity is 0.019 µg cm−2 and correlation coefficient is 0.951. The method is highly reproducible and has been applied to a wide variety of pharmaceutical formulations and the results compare favourably with those of official methods.

Facile homogeneous precipitation method to prepare MnO2 with high performance in catalytic oxidation of ethyl acetate

Altering the urea decomposition rate in the homogeneous precipitation progress enabled the formation of various morphologies of α-MnO 2 . The decrease in crystalline size led to an increase in the surface area and dominance of the (2 1 1) crystal plane. The abundant surface oxygen species and high reducibility related to unsaturated manganese played critical roles in the decomposition of ethyl acetate. • A facile method driven by a synchronous reaction of urea hydrolysis and potassium permanganate reduction was proposed. • Pure α-MnO 2 with various morphologies was obtained by tuning reaction parameters. • Oxygen species on the (2 1 1) crystal plane were found to be most active in oxidation. • The optimal α-MnO 2 catalyst exhibited high and stable catalytic performance. A facile homogeneous precipitation method driven by synchronous reactions of urea hydrolysis and potassium permanganate reduction is proposed for preparation of MnO 2 catalysts. Pure α-MnO 2 nanostructures with different morphologies, including nanowires, nanorods and nanoparticles, were obtained by simply tuning the precipitation conditions. The evolution of materials derived from different preparation conditions was investigated via X-ray diffraction, transmission electron microscopy, N 2 adsorption, X-ray photoelectron spectroscopy, chemisorption and DFT calculations. The precipitation temperature and time significantly influenced the physiochemical properties of as-prepared catalysts. With increasing precipitation temperature and time, the degree of crystallinity, BET surface area and amount of surface-adsorbed oxygen of α-MnO 2 exhibited a substantial increase. The main exposed surface facets varied from (2 0 0), (3 1 0) to (2 1 1) as temperature and time increased. The best precipitation temperature and time were 90 °C and 24 h respectively. The optimal α-MnO 2 catalyst demonstrated 100% conversion of 1000 ppm ethyl acetate under the high space velocity of 78,000 h −1 during a 113-h test at 190 °C, outperforming other manganese oxide catalysts and many typical noble metal catalysts in terms of activity and stability. Experimental results and DFT calculations were consistent and indicated that surface oxygen species originating from the (2 1 1) surface of α-MnO 2 were most active. This study provides important insights for manipulating the morphology of MnO 2 by a facile method and remarkably promoting the performance for ethyl acetate VOC elimination.

Structure and morphology of cryptomelane samples synthesized by different methods and their activity in the reaction of sulfur dioxide oxidation with air oxygen

The cryptomelane samples were synthesized by potassium permanganate reduction with manganese sulfate (reflux method) and also by KNO3 and MnSO4 melting together. Thus, all the obtained samples were characterized by XRD method, SEM, and FT-IR spectroscopy. Sizes of cryptomelane crystallites are in the range from 11 to 15 nm. The cryptomelane samples (0.5 g each) were tested at 20 °C, an initial SO2 concentration in the gas air mixture (GAM) of 150 mg/m3, and a GAM volume flow rate of 16.6 cm3/s. XRD, SEM, and FT-IR spectroscopic data show that cryptomelane interaction with SO2 is accompanied by formation of a new phase, MnSO4⋅H2O, and also by a decrease in cryptomelane phase content and its crystallite size.

Tuning surfactant-templates of nanorod-like cryptomelane synthesis towards vapor-phase selective oxidation of benzyl alcohol

In this study, nanorod-like cryptomelane was prepared via reduction of potassium permanganate in the presence of Tergitol (S1) and cetyltrimethylammonium bromide (CTAB, S2) as surfactant-templates. X-ray powder diffraction, scanning electron microscopy and N2 adsorption–desorption isotherms indicated the microporous nanorod-like cryptomelane structure. Element analysis revealed 7.5 wt% (S1) and 4.5 wt% (S1) of potassium while thermal gravimetricanalysis and temperature program desorption of oxygen revealed more active oxygen species over S2 catalyst, consisting to a lower H2 consumption over S2 (3.04 mmolH2/g) than that over S1 (3.55 mmolH2/g). Both Tergitol and CTAB surfactant-templates contributed to significant enhancement of their catalytic reactivity in vapor-phase oxidation of benzyl alcohol to benzaldehyde (rPhCHO = 68.6 and 74.6 mmolPhCHO/g.h at 280 °C over S1 and S2 catalysts, respectively). S1 catalyst possesses unique properties such as uniform nano-rod morphology, high thermal stability and considerable rPhCHO at 240–280 °C, adapting the industrial processes to produce chlorine-free benzaldehyde.

Soluble Colloidal Manganese Dioxide: Formation, Characterization and Application in Oxidative Kinetic Study of Ciprofloxacin

Soluble colloidal manganese dioxide was formed by reduction of potassium permanganate with sodium thiosulphate in neutral aqueous medium at 25 ºC. The obtained nano-sized colloidal manganese dioxide was found to be dark reddish-brown in color and stable for several months. The formation of manganese dioxide was confirmed by UV-visible spectrophotometer and determination of oxidation state of Mn species in manganese dioxide. The effect of different concentration of sodium thiosulphate on the formation of manganese dioxide was also studied. The nano-sized colloid manganese dioxide was characterized by transmission electron microscopy and Fourier transform infrared spectrophotometer. The formed soluble colloidal manganese dioxide was used as an oxidant in oxidation of ciprofloxacin in perchloric acid medium at 35 ºC. The reaction was first-order concerning to concentration of manganese dioxide and hydrogen ion but fractional order with ciprofloxacin. The results suggest formation of complex between ciprofloxacin and manganese dioxide. The oxidation products were also identified based on stoichiometric and characterization results. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Functional recovery of natural killer cell activity by nanoparticle‐mediated delivery of transforming growth factor beta 2 small interfering RNA

AbstractNatural killer (NK) cells are at the forefront of immunotherapies, as they have potent innate cytolytic effects on cancer cells. The success of NK cell therapies requires that they overcome immunosuppression in the tumor microenvironment. Tumors produce immunosuppressive factors like transforming growth factor beta (TGF‐β) that inhibit the effector functions of NK cells. Silencing of TGF‐beta signaling in NK cells is a potential approach to enhance their functions. However, transfection of NK cells by conventional methods is challenging. Here, we report the development of a nanoparticle (NP) system that delivers small interfering RNA for the TGF‐β receptor 2 (TGFBR2) into NK cells to restore their activation against cancer cells. Manganese dioxide NPs were synthesized by the reduction of potassium permanganate by poly (allylamine), which effectively complexed siRNA and protected it from degradation. The NPs were cytocompatible with NK cells and, upon loading with TGFBR2 siRNA, resulted in a 90% knockdown of the TGFBR2 receptor. NP‐mediated TGFBR2 receptor knockdown protected NK cells against TGF‐β suppression, which was studied in both two‐dimensional and three‐dimensional lung cancer cell culture systems. Namely, NK cells treated with TGFBR2 siRNA loaded NPs demonstrated higher interferon gamma production, infiltration, and killing of lung cancer cells compared with control NK cells. This study demonstrates the feasibility of NP‐mediated RNA interference in NK cells to increase their resilience to the immunosuppressive environments in solid tumors.

Effect of morphology of manganese oxide on the capacitive behavior of electrodes

Manganese oxide (MnO2) was synthesized by reduction of potassium permanganate followed by calcination in air at 200, 400 and 600 °C. Morphology and structure of MnO2 was characterized by scanning electron microscopy and x-ray diffraction, respectively. Electrochemical characterization of MnO2-based electrodes was carried out by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). CV results revealed that MnO2-based electrode calcined at 200 °C showed maximum specific capacitance of 177 F g−1 at a scan rate of 1 mVs−1 in 3 M potassium hydroxide. EIS analysis of electrode produced with MnO2 that was calcined at 200 °C showed solution resistance and charge transfer resistance values of 0.421 and 1.605 Ω, respectively. CV results also revealed that MnO2-based electrodes showed capacitance retention of 89 % at 50 mVs−1 scan rate for 1000 cycles.

Leaf Disc Assays for Rapid Measurement of Antioxidant Activity

Antioxidant levels are key parameters for studies of food quality, stress responses, and plant health. Herein, we have demonstrated that excised leaf disc has both radical scavenging activity and reducing power, and used this concept to develop 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and potassium permanganate reduction (PPR) leaf disc assays. Reaction time and reagent concentration for these assays were optimized using leaves from spinach, kale, collards, mustard, and watermelon. Further, these assays were validated for linearity and intra-assay precision. Ultra-high performance liquid chromatography coupled to an electrospray quadrupole time-of-flight mass spectrometer (UPLC/ESI-HR-QTOFMS) was used for phytochemical profiling and studying relative abundances of certain phenolic compounds in various leaf discs suspended and cell-free extracts. The mass spectral analysis showed that leaf disc suspended methanolic extracts had almost same phytochemical profiles to those of cell-free extracts. The DPPH leaf disc assay demonstrated better radical scavenging potential than the conventional cell-free extract method. By contrast, the observed antioxidant activity values in ABTS and PPR leaf disc assays were lower than those of conventional cell-free extract-based methods. In conclusion, the developed leaf disc assays are simple and rapid for the qualitative and comparative assessment of the antioxidant potential of leaf samples, as well as can be a good alternative to conventional cell-free extract based methods.

Colorimetric detection of pyrethroid metabolite by using surface molecularly imprinted polymer

A simple colorimetric method was developed for the detection of 3-Phenoxybenzaldehyde (3-PBD), the metabolite of pyrethroid pesticides, based on surface molecularly imprinted polymer (MIP). In this method, MIP layer was coated on the surface of monodispersed silica nanoparticles via sol-gel process with 3-Aminopropyltriethoxysilane (APTES) and phenyltrimethoxysilane (PTES) as monomers. Compare with single functional monomer, APTES and PTES can interact with 3-PBD mainly by hydrogen bonding and π-π staking interaction, which makes the synthetic MIPs show better affinity and absorption capacity towards target than that of signal functional monomer. After eluted from MIP nanoparticles, the 3- PBD resulted in a distinctive color fading by potassium permanganate reduction. Taking advantage of this phenomenon, the 3- PBD could be detected by recording the absorption of potassium permanganate solution with MIPs as the recognition element. The MIPs, synthesized under various conditions, were characterized by fourier transform infrared spectrometry and scanning electro microscopy. Meanwhile, their absorption performance were also investigated. Under the optimum condition, the proposed method exhibited a linear concentration range of 3-PBD from 0.1μgmL−1 to 1μgmL−1 with a lower detection limit of 0.052μgmL−1 (S/N=3). Moreover, this method was further used to detect 3-PBD in real samples form river water, fruit juice, and beverage. Satisfactory recovery was achieved in the range of 90.0∼98.9%, which clearly demonstrating the potential value of this strategy in the detection of total pyrethroid pesticides.

Physicochemical properties of manganese oxides obtained via the sol–gel method: The reduction of potassium permanganate by polyvinyl alcohol

Experimental data on the sol–gel synthesis of manganese oxides formed during the reduction of potassium permanganate by polyvinyl alcohol in an aqueous medium are presented. The physicochemical properties of the obtained manganese oxide systems that depend on the conditions of the synthesis are studied by means of DTA, XRD, SEM, and the low temperature adsorption–desorption of nitrogen. It is found that the obtained samples have a mesoporous structure and predominantly consist of double potassium–manganese oxide K2Mn4O8 with a tunnel structure and impurities of oxides such as α-MnO2, MnO, α-Mn2O3, and Mn5O8. It is shown that the proposed method of synthesis allows us to regulate the size and volume of mesopores and, to a lesser extent, the texture of the obtained oxides, which can be considered promising sorbents for the selective extraction of strontium and cesium ions from multicomponent aqueous solutions.

Sorption of strontium ions onto mesoporous manganese oxide of OMS-2 type

Sorption of stable and radioactive strontium ions onto mesoporous manganese oxide of OMS-2 type, prepared by the sol–gel method via reduction of potassium permanganate with polyvinyl alcohol in aqueous medium, was studied. The influence exerted by the pore structure parameters and by the phase and chemical composition of manganese oxide on its sorption properties and selectivity to Sr ions was examined. Manganese oxide samples prepared using a 0.1 wt % KMnO4 solution exhibit the highest values of the sorption capacity for Sr, about 100–150 mg g–1, and of the Sr distribution coefficient, K d = (11.5–19.5) × 103 cm3 g–1. Introduction of 0.1 M NaCl into this solution considerably decreases the sorption of stable Sr ions, and for all the samples the sorption capacity is 25–35 mg g–1. On the other hand, for the most active sorbents the distribution coefficient in the presence of 0.1 M NaCl increases by a factor of approximately 8–10 relative to distilled water and reaches (91–208) × 103 cm3 g–1. Introduction of 0.05 M CaCl2 also decreases the Sr uptake, and the sorption capacity of the most active sorbents for stable Sr ions is 25–35 mg g–1 at K d (85Sr) equal to (0.14–0.35) × 103 cm3 g–1.